JP2008126998A - Steering device for completely concentrating axle directions of whole wheels - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To put a steering device to practical use, which completely concenters the turning centers of the whole wheels of a four-wheeled vehicle and the like, steers the wheels by driving a link, and sets rotation radial to zero or substantially to zero. <P>SOLUTION: (1) Left and right rods 7, 6 steering the wheels are connected to each other through a shaft (control shaft 12) and are formed bendable in a V shape. (2) The length of the left and right rods 7, 6 is adjusted, a shape easily controlled is selected from the moving loci of the shaft (control shaft 12) when the turning centers of the whole wheels are concentered and moved, and an inverted V-shape cam groove 21 matching with the shape is formed. (3) The shaft (control shaft 12) fitted into the cam groove 21 is moved in both directions by a lever or the like, and the whole wheels are steered by the left and right rods 7, 6. The steering device is configured as described above, thereby the turning centers of the whole wheels match with each other in any steering position. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  A steering device technology that turns the axles of all wheels, such as a four-wheeled vehicle, in a completely concentrated manner and enables turning at or near the turning radius of the vehicle body.

  For example, when steering the front wheel, there is a so-called Ackermann-Jantou system in which all the wheels move on a concentric circle so that the extension line of the link (knuckle arm) intersects at the center of the rear axle. However, this is an approximate state, and in reality, all the axles are not concentrated at one point, and the more the steering angle is increased, the more dissociated. Further, it has been difficult for a link-type steering device to steer the rotating wheel about 90 degrees and turn the vehicle body at the stop position.

Problems to be solved by the invention

  Practical application of a steering device with links that allows the axle direction of all wheels such as a four-wheel vehicle to be concentrated at a single point at any steering position and turn the vehicle body in all directions even at a stop position.

Means for solving the problem

(A) The central part of the steering tie rods attached to the left and right wheels is coupled in a V-shape so as to be refractable by axial coupling.
(B) Adjusting the length of the tie rod and selecting the front and rear positions of its axis (control shaft 12), V-shaped cam that matches the movement trajectory of the moving axis in a state where all the axles are completely matched, and is easy to control The shape of the groove 21 is selected.
(C) The wheel is steered by moving the above-mentioned shaft (control shaft 12) left and right in the cam groove 21 with a lever or the like that can be refracted.

The invention is illustrated by examples. FIG. 1 is a plan view of the electric wheelchair, and the right half shows a state where the chair 8 is removed. The left and right front wheels 1 and the rear wheels 2 have a four-wheel configuration with the same front and rear diameters that can cope with steps and rough roads, and can steer by steering the rear wheel 2 on one side up to a maximum of 90 degrees. The left and right rear wheels 2 are mounted on the support shafts 11 at both ends of the rear frame 4 integrated with the side frame 3, and the wheels are steered by the movement of the right rod 6 and the left rod 7. The rear wheel 2 indicated by the dotted line is the position when turning around the right under the left front wheel. The axle direction of all the wheels is concentrated in that direction, and the vehicle turns forward with the ground contact part of the left front wheel as the turning center. You can turn right in reverse and turn in all directions.
FIG. 2 illustrates steering means for the rear wheel, and shows the operation of the wheel by the steering device 5, the right rod 6 and the left rod 7. Regardless of the position of the control shaft 12 in the V-shaped cam groove 21, the entire axle direction is completely concentrated on one point. When the control shaft 12 is moved, the right rod 6 and the left rod 7 are moved. To steer the right wheel 17 and the left wheel 18 in the required direction. The position of the wheel indicated by the dotted line represents the position when the drive shaft 13 is rotated in the right direction every quarter of the movement range. When the maximum left wheel 18 is rotated 90 degrees, the turning center is further inside than the example in FIG. Although there is a restriction based on the link method, it is also possible to place the turning center slightly inside. The shape of the V-shaped cam groove 21 is adjusted by adjusting the length of the rod and changing the front / rear position of the control shaft 12, so that the control shaft 12 can be easily controlled.
The shape of the cam groove 21 will be described with reference to FIG. When the position of the control shaft 12 at the center of the left and right wheels is in a straight line with the left and right steering shafts 14, the movement trajectory of the cam groove 21 that concentrates all the axles at one point makes the rods A and a longer. As an example of shifting the position of the control shaft 12 downward, only B and b, C and c, and lower D are shown. Both are arranged in the upper and lower directions, but the arrangement state of the rods and the like indicated by the solid line is the B state. With link driving, control is difficult in the case of abc. In the case of the lower ABC, the longer the rod is moved and the lower the angle is, the larger the angle becomes, and the position of the steering device 5 becomes farther, and the pitch deviation of the steering angle by steering becomes larger. The position of about BC does not make the rod longer, and smooth control is possible. 1 to 5 all show such a positional relationship. Further, when the attachment position of the steering shaft 14 is set further inside, the V-shaped cam groove becomes flatter. Moreover, since it becomes a steeper shape when it shifts outside, the position which becomes V shape which is easy to control is selected. The steering shaft 14 or the like at the joint between the left and right rods 7 and 6 and the wheel can be replaced with a ball joint or the like as in the conventional case. 3 and 4 show a structural example of the steering device 5 that drives the left and right rods and wheels in this manner. The control shaft 12 at the joint of the left and right rods 7 and 6 that are arranged as shown in FIG. 2 and steers the wheel is fitted in a V-shaped cam groove 21 via a needle bearing so as to be able to roll. A main arm 19 is attached to a drive shaft 13 that is rotated left and right by the motor 10, and an arm 20 is coupled by a connecting shaft 24, and the other end is attached to support the control shaft 12. The left and right rods 7 and 6 are similarly fitted to the control shaft 12. A cam plate 22 having a cam groove 21 is fixed to the case 23. When the drive shaft 13 and the main arm 19 attached thereto are rotated to the right in this structure, the control shaft 12 supported up and down by the slave arm 20 moves to the upper end while rolling in the cam groove 21. To do. In the case of left rotation, it can be moved to the lower end in the same manner. The states of the main arm 19 and the slave arm 20 at that time are indicated by dotted lines. In this example, the cam plate 22 is provided at the center, but it may be divided into two on the upper and lower sides, that is, on the outer side of the slave arm 20.
The driving control is exemplified by the driving lever 15 used in the current electric wheelchair. The steering wheel 5 is driven by the steering motor 10 and steered forward and backward by the electric motor 9 of the rear wheel after tilting forward and backward. Unlike small freewheels, the wheel diameter is large, and steering the front wheels causes problems during getting on and off and steering, so the rear wheels are steered. However, sufficient space for the battery 16 and the like can be secured. Not only two-wheel steering but also six-wheeled vehicles such as four-wheelers and trailers can be handled.
FIG. 5 shows an example of steering by four-wheel steering, and the direction of each wheel when turning around the middle of the upper front wheel 1 and rear wheel 2 is indicated by a dotted line. In this case, the left and right rods and the steering device are arranged symmetrically, but the structure and function are the same as in the case of two-wheel steering. In this case, both the steering devices are rotated in the opposite direction synchronously by the connecting shaft 24. Further, as in the case of two-wheel steering, the turning center can be freely selected as long as it can be controlled smoothly. Of course, the shape of the cam groove 21 changes as described above. This four-wheel steering can also be applied to ordinary passenger cars, but if it is equipped with a truck for transporting cargo, it is very effective in driving operations such as turning in narrow spaces. In addition, the forward movement of the turning center in the direction of the axle required in response to the centrifugal force applied to the vehicle body at high speed can be achieved by slightly rotating the cam plate 22 around the refraction point of the cam groove 21 or shifting it back and forth. Yes. In the case of four-wheel steering, the same measures can be taken by providing a differential on the front and rear connecting shafts 24.

The invention's effect

(A) The vehicle can turn with a turning radius of zero or a very small radius around or under the vehicle, and can change direction at a stop position in a narrow place.
(B) Steering can be performed by steering the axles of all wheels so that they are completely concentrated on one point, and there is less slipping on the contact surface, reducing tire wear.
(C) Since the wheels are steered by the link mechanism, the entire steering device is simplified.
(D) The turning center point required at high speed can be easily shifted.

は前後四輪を操舵する状態を示す。 はタイロッドの長さを変えた時の制御軸１２の位置と、全車輪の旋回中心を集中させるのに必要な制御軸１２の移動軌跡を表した図。 These are top views of the example which applied the steering device of this invention to the electric wheelchair. 1 shows steering means for concentrating the axles of all the wheels in FIG.

Indicates the state of steering the front and rear four wheels. FIG. 4 is a diagram showing the position of the control shaft 12 when the length of the tie rod is changed and the movement locus of the control shaft 12 necessary for concentrating the turning center of all the wheels.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front wheel 2 Rear wheel 3 Side frame 4 Rear frame 5 Steering device 6 Right rod 7 Left rod 8 Chair 9 Motor 10 Motor 11 Support shaft 12 Control shaft 13 Driving shaft 14 Steering shaft 15 Driving lever 16 Battery 17 Right wheel 18 Left wheel 19 Main arm 20 Slave arm 21 Cam groove 22 Cam plate 23 Case 24 Connecting shaft

Claims (2)

(A) The central part of the left and right tie rods that steer the wheels are connected by a shaft so that they can be bent freely in a V shape.
(B) Regardless of the steering position where the axle direction of all wheels is, it moves or rolls in a V-shaped cam groove 21 that matches the movement locus of the above-mentioned shaft (control shaft 12) that is completely concentrated at one point. Install the shaft as possible.
(C) A drive device such as a refraction lever for moving the control shaft 12 to the right or left side in the V-shaped cam groove 21 is provided.
A steering apparatus such as a four-wheeled vehicle configured as described above that concentrates the axle directions of all the wheels completely at one point.   In the case of four-wheel steering, a differential device is provided between the devices before and after the connection, or the cam groove 21 is slightly rotated and displaced around the V-shaped refraction point of one cam groove 21, or the cam groove 21 is moved forward and backward. The steering apparatus according to the above item, which enables the movement of the turning center of the rear wheel required during high-speed driving by means of moving.

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